Breeding for Agrobiodiversity: Strategies to Tackle Climate Extremes – By Rajaram Karki || Krishi Vines

Introduction

In the face of climate change, agriculture must adapt to increasingly unpredictable and extreme weather patterns. Rising temperatures, erratic rainfall, prolonged droughts, and intense storms are becoming the new normal. These climate extremes threaten global food security by reducing crop yields, damaging ecosystems, and increasing the vulnerability of agricultural systems. One of the most effective strategies to enhance agricultural resilience is through breeding for agrobiodiversity—the deliberate development of diverse crop varieties that can withstand climate stresses while promoting sustainability.

The Role of Agrobiodiversity in Resilience

Agrobiodiversity refers to the variety of crops, livestock, and microorganisms that contribute to farming systems. It includes both genetic diversity within species and the diversity of species used in agriculture. Greater diversity in agricultural systems offers several benefits, such as enhancing ecosystem stability, improving soil health, and reducing the impact of pests and diseases. Most importantly, agrobiodiversity can play a crucial role in climate adaptation, as different species and varieties possess varying degrees of resilience to environmental stresses.

Climate Extremes and Their Impact on Crops

Climate extremes, such as droughts, heatwaves, floods, and storms, have far-reaching effects on crop production. For example:

• Drought reduces water availability, limiting plant growth and productivity.
• Heat stress affects pollination, causes flower and fruit drop, and can lead to poor seed set.
• Flooding can cause soil erosion, nutrient leaching, and damage to root systems.
• Salinity in coastal areas, exacerbated by sea-level rise, reduces the ability of plants to absorb water.

These stresses vary by region, but the need for crops that can survive and thrive under such conditions is universal. This is where breeding for agrobiodiversity becomes essential.

Breeding for Climate-Resilient Crops

Crop breeding is the science of improving plant species for better yields, disease resistance, and environmental tolerance. To tackle climate extremes, breeders focus on enhancing genetic diversity in crops, developing varieties that possess traits suitable for different climatic conditions. Some of the key strategies include:

1. Drought-Resistant Varieties: Breeders are developing crops with deep root systems, increased water-use efficiency, and the ability to maintain productivity under low water conditions. For instance, drought-resistant maize and sorghum are being cultivated in arid regions.
2. Heat-Tolerant Crops: Temperature increases negatively affect crop yields, particularly during flowering and seed development. Breeding for heat-tolerant rice and wheat varieties helps reduce the risk of crop failure in regions prone to heatwaves.
3. Salt-Tolerant Varieties: In coastal and saline-prone areas, salt-tolerant crops like barley and certain varieties of rice are being bred to maintain productivity even in soils affected by salinization due to rising sea levels.
4. Flood-Resistant Crops: To combat the effects of flooding, submergence-tolerant rice varieties, such as “Scuba rice,” have been developed. These can survive prolonged periods of submergence and resume growth once floodwaters recede.
5. Early-Maturing Varieties: In regions where the growing season is shortened due to erratic weather, early-maturing crop varieties allow farmers to complete their cropping cycle before the onset of harsh conditions. Crops like early-maturing millet and cowpea are examples of this approach.
6. Polyploid Breeding: Polyploid crops, which contain multiple sets of chromosomes, often display greater resilience to environmental stresses. Polyploidy can enhance traits such as drought tolerance and resistance to temperature extremes. Cotton and certain fruit trees benefit from polyploid breeding programs.

Incorporating Wild Relatives and Landraces

Wild crop relatives and traditional landraces (local varieties that have adapted over centuries to specific environments) are crucial sources of genetic diversity for breeding. Many of these species possess traits that modern, high-yielding crops lack, such as resilience to extreme temperatures, pests, or poor soils.

For example, wild relatives of wheat and potatoes have been used to introduce traits like drought tolerance and disease resistance into modern cultivars. By tapping into these untapped genetic resources, breeders can develop crops that are better suited to the challenges of climate change.

Participatory Breeding and Farmer Involvement

Farmers, especially those in marginal environments, have long practiced traditional methods of seed selection and crop breeding. Involving them in formal breeding programs through participatory plant breeding ensures that new varieties meet the needs of local communities and are adapted to specific environmental conditions. This approach enhances agrobiodiversity by fostering the development of diverse, locally adapted crop varieties.

The Role of Biotechnology in Crop Breeding

Advances in biotechnology, such as genome editing and marker-assisted selection, have accelerated the pace of breeding for climate resilience. These tools allow breeders to identify and incorporate desirable traits into crops more efficiently than traditional methods. For example, CRISPR technology has been used to create rice varieties that are more tolerant to drought and flooding.

While biotechnology has great potential, it must be applied carefully to avoid reducing agrobiodiversity. Maintaining a broad genetic base is essential to ensuring that crops remain resilient in the face of future environmental changes.

Conclusion

Breeding for agrobiodiversity is not just about producing higher yields; it is about developing agricultural systems that are resilient, sustainable, and adaptable to the challenges posed by climate extremes. By embracing the diversity of plant genetic resources and combining modern breeding techniques with traditional knowledge, we can ensure that farming systems are better equipped to handle the uncertainties of a changing climate.

Ultimately, a diverse and resilient agricultural system will be key to securing food production in a world where climate extremes are becoming increasingly common. Through strategic breeding efforts, the potential of agrobiodiversity can be harnessed to create crops that not only survive but thrive in a rapidly changing environment.